Field of the Invention
The invention relates to a laundry drum for a washing machine, having sheet-metal wall portions with holes for the passage of such treatment media as water or air, and surrounding regions facing toward the outside of the laundry drum being elongated into a tuliplike or frustoconical shape. The invention also relates to a tool for producing the laundry drum, having a guided hole-cutting needle and a stiffening piece with a cutting hole to be put in place for bracing below the level of the sheet-metal wall portions.
One such laundry drum is known from German Utility Models DE 1 756 317 U and DE 66 06 902 U. In the production of the laundry drum shown in German Utility Model DE 1 756 317 U, evidently each flow hole is first stamped out, before its tulip is drawn out. That can be seen in FIGS. 1 and 2 of German Utility Model DE 1 756 317 U from the fact that the edges of the holes are oblique to the normal on the drum jacket.
Conversely, in German Utility Model DE 66 06 902 U, the shape of the flow holes of a washing machine drum is shown in idealized form. Such flow holes are in fact, still today, typically made in the manner shown herein in FIG. 1 and discussed below.
In the prior art, burrs on the outermost edge of the sheet metal at the holes are dangerous to the fingertips and to laundry fibers that might pass through the flow holes and become caught.